A large-aperture day and night co-focus fisheye lens

Abstract

This utility model relates to the field of optical lens technology, and more particularly to a large-aperture confocal day and night fisheye lens. The lens comprises, along its optical axis from object to image, the following elements arranged sequentially: a first lens with negative optical power; a second lens with negative optical power; a third lens with negative optical power; a fourth lens with negative optical power; a fifth lens with positive optical power; a sixth lens with positive optical power; a seventh lens with negative optical power; an eighth lens with positive optical power; a ninth lens with positive optical power; a tenth lens with negative optical power; an eleventh lens with positive optical power; and a twelfth lens with positive optical power. The seventh and eighth lenses, as well as the ninth and tenth lenses, are cemented lenses. This lens employs 12 spherical glass lenses, effectively correcting system aberrations, meeting the requirements of an aperture F# ≥ 1.0 and a focal length f ≥ 1.38mm. It can be matched with high-pixel chips, ensuring the system's optical performance and enabling the lens to achieve large-aperture confocal day and night.

Description

Technical Field

[0001] This utility model relates to the field of optical lens technology, and in particular to a large-aperture day and night confocal fisheye lens. Background Technology

[0002] A fisheye lens is a special type of lens with a short focal length and an ultra-wide angle of view, typically between 180° and 270°. Its visual effect is similar to a fish observing objects on the water's surface. To achieve this extremely wide angle of view, the front lens of a fisheye lens has a short diameter and protrudes parabolically towards the front of the lens, resembling a fish's eye, hence its name. Due to its exceptionally wide angle of view, fisheye lenses are widely used in security monitoring, action cameras, and automotive imaging.

[0003] With the continuous development of optical technology and the security industry, the application of surveillance equipment is becoming increasingly widespread. The market demands lenses with large field of view, large lens surface area, large aperture, high-definition resolution exceeding 4K, smaller lens size, and high edge illumination, while also requiring functionalities such as waterproofing and day / night focusing. Currently available fisheye lenses have relatively small apertures and low resolution, making it difficult to meet these growing demands. Utility Model Content

[0004] To solve the above-mentioned technical problems, this utility model provides a large-aperture day and night confocal fisheye lens, which adopts 12 glass spherical lenses, has a total lens length of ≤30mm, and an aperture of F#≥1.0, which can meet the current market demand for fisheye lenses in security monitoring, vehicle-mounted and other fields.

[0005] The objective of this utility model is achieved through the following technical solution: A large-aperture confocal day and night fisheye lens defines the surface of the lens adjacent to the object plane as the object-side surface and the surface of the lens adjacent to the image plane as the image-side surface, arranged sequentially from the object-side to the image-side along the lens optical axis: The first lens is a spherical glass lens with negative optical power, wherein the object side is convex and the image side is concave. The second lens is a spherical glass lens with negative optical power, whose object side is convex and image side is concave. The third lens is a spherical glass lens with negative optical power, whose object side is convex and image side is concave. The fourth lens is a spherical glass lens with negative optical power, wherein the object side is concave and the image side is concave. The fifth lens is a spherical glass lens with positive optical power, whose object side is convex and image side is convex. The sixth lens is a spherical glass lens with positive optical power, and its object side and image side are both convex. The seventh lens is a spherical glass lens with negative optical power, whose object side is convex and image side is concave. The eighth lens is a spherical glass lens with positive optical power, whose object side is convex and image side is convex. The ninth lens is a spherical glass lens with positive optical power, the object side of which is convex and the image side of which is convex. The tenth lens is a spherical glass lens with negative optical power, the object side of which is concave and the image side of which is convex. The eleventh lens is a spherical glass lens with positive optical power, and its object side and image side are both convex. The twelfth lens is a spherical glass lens with positive optical power, whose object side is convex and image side is concave. The image-side surface of the seventh lens and the object-side surface of the eighth lens are cemented together to form a first cemented lens. The image-side surface of the ninth lens and the object-side surface of the tenth lens are cemented together to form a second cemented lens.

[0006] Furthermore, the lens is also configured along its optical axis as follows: An aperture stop is provided, wherein the aperture stop is disposed between the sixth lens and the seventh lens, or the aperture stop is disposed between the fifth lens and the sixth lens; A filter, the filter being disposed on the image-side surface of the twelfth lens; A protective glass and an image acquisition element, wherein the protective glass is integrated on the image acquisition element, and the image acquisition element is disposed on the image side of the protective glass.

[0007] Furthermore, in this invention, considering the aberrations of the optical system and the different focal distances, the focal lengths, refractive indices, and radii of curvature of the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, and twelfth lenses respectively satisfy the following conditions:

[0008] Where f1 is the focal length of the first lens, ND1 is the refractive index of the first lens, R11 is the radius of curvature of the object side surface of the first lens, and R12 is the radius of curvature of the image side surface of the first lens. f2 is the focal length of the second lens, ND2 is the refractive index of the second lens, R21 is the radius of curvature of the object side surface of the second lens, and R22 is the radius of curvature of the image side surface of the second lens. f3 is the focal length of the third lens, ND3 is the refractive index of the third lens, R31 is the radius of curvature of the object side of the third lens, and R32 is the radius of curvature of the image side of the third lens. f4 is the focal length of the fourth lens, ND4 is the refractive index of the fourth lens, R41 is the radius of curvature of the object side of the fourth lens, and R42 is the radius of curvature of the image side of the fourth lens. f5 is the focal length of the fifth lens, ND5 is the refractive index of the fifth lens, R51 is the radius of curvature of the object side of the fifth lens, and R52 is the radius of curvature of the image side of the fifth lens. f6 is the focal length of the sixth lens, ND6 is the refractive index of the sixth lens, R61 is the radius of curvature of the object side surface of the sixth lens, and R62 is the radius of curvature of the object side surface of the sixth lens. f7 is the focal length of the seventh lens, ND7 is the refractive index of the seventh lens, R71 is the radius of curvature of the object side of the seventh lens, and R72 is the radius of curvature of the image side of the seventh lens. f8 is the focal length of the eighth lens, ND8 is the refractive index of the eighth lens, R81 is the radius of curvature of the object side of the eighth lens, and R82 is the radius of curvature of the image side of the eighth lens. f9 is the focal length of the ninth lens, ND9 is the refractive index of the ninth lens, R91 is the radius of curvature of the object side of the ninth lens, and R92 is the radius of curvature of the image side of the ninth lens. f10 is the focal length of the tenth lens, ND10 is the refractive index of the tenth lens, R101 is the radius of curvature of the object side of the tenth lens, and R102 is the radius of curvature of the image side of the tenth lens. f11 is the focal length of the eleventh lens, ND11 is the refractive index of the eleventh lens, R111 is the radius of curvature of the object surface of the eleventh lens, and R112 is the radius of curvature of the object surface of the eleventh lens. f12 is the focal length of the twelfth lens, ND12 is the refractive index of the twelfth lens, R121 is the radius of curvature of the object side of the twelfth lens, and R122 is the radius of curvature of the image side of the twelfth lens. Focal length: "+" indicates that the lens has positive power, and "-" indicates that the lens has negative power. The unit is mm. Radius of curvature: "+" indicates that the surface bends toward the image plane, and "-" indicates that the surface bends toward the object plane. The unit is mm.

[0009] Furthermore, in this invention, to achieve better performance of the optical system, we need to rationally select lens materials, rationally allocate the focal lengths of each lens, and rationally optimize the optical system during the design process to correct system aberrations and ultimately optimize the performance of the optical system. The ratio of the focal length of each lens to the total focal length of the lens also satisfies the following conditions: -11.1≤f1 / f≤-10.81; -8.36≤f² / f≤-7.35; -8.75≤f3 / f≤-6.79; -2.40≤f4 / f≤-2.24; 3.64≤f5 / f≤4.00; 7.56≤f6 / f≤8.97; -4.61≤f7 / f≤-3.76; 3.82≤f8 / f≤4.16; 4.01≤f9 / f≤4.36; -3.68≤f10 / f≤-3.06; 5.69≤f11 / f≤6.46; 7.36≤f12 / f≤8.88; 23.55 < f78 / f < 36.89; -47.86 < f91 / f < -22.19.

[0010] In the formula, f is the focal length of the lens optical system, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, f8 is the focal length of the eighth lens, f9 is the focal length of the ninth lens, f10 is the focal length of the tenth lens, f11 is the focal length of the eleventh lens, f12 is the focal length of the twelfth lens, f78 is the focal length of the first cemented lens, and f91 is the focal length of the second cemented lens.

[0011] Furthermore, in this utility model, The lens aperture is F#, satisfying F#≥1.0; The field of view of the lens is FOV, which satisfies FOV≤200°; The total optical length of the lens is TTL, which satisfies TTL≤30mm; The total focal length of the lens is f, which satisfies f≥1.38mm; The optical back focal length of the lens is OBFL, which satisfies OBFL≥3mm.

[0012] Furthermore, in this invention, the lens also satisfies the following relationship: IC / TTL ≥ 0.14; TTL / f≤20.6; OBFL / TTL ≥ 0.1; In the formula, f is the total focal length of the lens, TTL is the total optical length of the lens, OBFL is the optical back focal length of the lens, the optical back focal length of the lens is the distance from the point on the image side of the twelfth lens closest to the image plane to the image plane, and IC is the full image height of the chip paired with the lens system.

[0013] The beneficial effects of this utility model are: This invention uses 12 spherical glass lenses. By combining different shapes of the lenses and a reasonable distribution of optical power, the lens achieves good optical performance and a compact, non-bulky structure.

[0014] In terms of performance, the 12 spherical glass lenses can effectively correct system aberrations, ensure the optical performance of the system, and enable the lens to achieve large aperture day and night co-focus. The entire optical system meets the requirements of aperture F#≥1.0, large light transmission diameter, focal length f≥1.38mm, good imaging performance in all fields of view, and can be matched with high-pixel chips.

[0015] Structurally, the lens achieves clear images at both high temperatures of +85℃ and low temperatures of -40℃ through the combination of different materials and reasonable optical power of the lenses. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the optical structure of Embodiment 1 of the present invention; Figure 2 The MTF curve of visible light 0.435-0.656μm (200lp / mm) in Embodiment 1 of this utility model is shown. Figure 3 The MTF curve of infrared light at 0.850μm (200lp / mm) in Embodiment 1 of this utility model is shown. Figure 4 This is a high-temperature +85℃ defocusing curve of visible light 0.435-0.656μm (125lp / mm) in Embodiment 1 of this utility model; Figure 5 This is a low-temperature defocusing curve at -40℃ for visible light 0.435-0.656μm (125lp / mm) in Embodiment 1 of this utility model; Figure 6 This is a relative illuminance diagram for visible light at 0.546 μm in Embodiment 1 of this utility model; Figure 7 This is a schematic diagram of the optical structure of Embodiment 2 of the present invention; Figure 8 The MTF curve for visible light 0.435-0.656μm (200lp / mm) in Embodiment 2 of this utility model is shown. Figure 9 The MTF curve of infrared light at 0.850μm (200lp / mm) in Embodiment 2 of this utility model is shown. Figure 10 This is a high-temperature +85℃ defocusing curve of visible light 0.435-0.656μm (125lp / mm) in Embodiment 2 of this utility model; Figure 11 This is a low-temperature defocusing curve at -40℃ for visible light 0.435-0.656μm (125lp / mm) in Embodiment 2 of this utility model; Figure 12 This is a relative illuminance diagram for visible light at 0.546 μm in Embodiment 2 of this utility model; Reference numerals: 1-First lens, 2-Second lens, 3-Third lens, 4-Fourth lens, 5-Fifth lens, 6-Sixth lens, 7-Seventh lens, 8-Eighth lens, 9-Ninth lens, 10-Tenth lens, 11-Eleventh lens, 12-Twelfth lens, 13-Aperture stop, 14-Filter, 15-Protective glass, 16-Image acquisition element. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. In this specification, the expressions "first," "second," "third," etc., are only used to distinguish one feature from another, and do not indicate any limitation on the features. The shape of the spherical or aspherical surface is not limited to the spherical or aspherical shapes shown in the drawings. The drawings are for illustrative purposes only and are not strictly drawn to scale.

[0018] In this invention, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region; if the lens surface is not defined as convex, concave, or flat, it means that the lens surface can be convex, concave, or flat. The surface of each lens closest to the object being photographed is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0019] Unless otherwise specified, all terms used in this invention (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the same meaning as they have in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense, unless expressly so defined in this invention.

[0020] It should be noted that, where there is no conflict, the embodiments and features in the embodiments of this utility model can be combined with each other. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

[0021] This utility model provides a large-aperture confocal day and night fisheye lens. The surface of the lens adjacent to the object plane is the object-side surface, and the surface of the lens adjacent to the image plane is the image-side surface. Along the lens optical axis, from the object side to the image side, a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10, an eleventh lens 11, and a twelfth lens 12 are arranged sequentially. The lens also has an aperture stop 13, a filter 14, a protective glass 15, and an image acquisition element 16 along the lens optical axis. The aperture stop 13 is located between the sixth lens 6 and the seventh lens 7, or between the fifth lens 5 and the sixth lens 6. The filter 14 is located on the image-side surface of the twelfth lens 12, and the image acquisition element 16 is located on the image-side surface of the protective glass 15, which is integrated into the image acquisition element 16.

[0022] in: The first lens 1 is a spherical glass lens with negative optical power, its object side is convex and its image side is concave. The second lens 2 is a spherical glass lens with negative optical power, its object side is convex and its image side is concave. The third lens 3 is a spherical glass lens with negative optical power, its object side is convex and its image side is concave. The fourth lens 4 is a spherical glass lens with negative optical power, and its object side is concave and its image side is concave. The fifth lens 5 is a spherical glass lens with positive optical power, and its object side and image side are both convex. The sixth lens 6 is a spherical glass lens with positive optical power, and its object side and image side are both convex. The seventh lens 7 is a spherical glass lens with negative optical power, its object side is convex and its image side is concave. The eighth lens 8 is a spherical glass lens with positive optical power, and its object side is convex and its image side is convex. The ninth lens 9 is a spherical glass lens with positive optical power, and its object side and image side are both convex. The tenth lens 10 is a spherical glass lens with negative optical power, its object side is concave and its image side is convex; The eleventh lens 11 is a spherical glass lens with positive optical power, and its object side and image side are both convex. The twelfth lens 12 is a spherical glass lens with positive optical power, its object side is convex and its image side is concave. The image-side surface of the seventh lens 7 and the object-side surface of the eighth lens 8 are cemented together to form the first cemented lens; The image-side surface of the ninth lens 9 and the object-side surface of the tenth lens 10 are cemented together to form a second cemented lens. In this invention, to achieve better performance of the optical system, the design process involves rationally selecting lens materials, rationally allocating the focal lengths of each lens, and rationally optimizing the optical system to correct aberrations and ultimately optimize its performance. In this invention, the focal lengths of the first lens 1 are f1, the second lens 2 is f2, the third lens 3 is f3, the fourth lens 4 is f4, the fifth lens 5 is f5, the sixth lens 6 is f6, the seventh lens 7 is f7, the eighth lens 8 is f8, the ninth lens 9 is f9, the tenth lens 10 is f10, the eleventh lens 11 is f11, the twelfth lens 12 is f12, the first cemented lens is f78, the second cemented lens is f91, and the total focal length of the lens is f. The ratio of the focal length of each lens to the total focal length of the system satisfies the following condition: -11.1≤f1 / f≤-10.81; -8.36≤f² / f≤-7.35; -8.75≤f3 / f≤-6.79; -2.40≤f4 / f≤-2.24; 3.64≤f5 / f≤4.00; 7.56≤f6 / f≤8.97; -4.61≤f7 / f≤-3.76; 3.82≤f8 / f≤4.16; 4.01≤f9 / f≤4.36; -3.68≤f10 / f≤-3.06; 5.69≤f11 / f≤6.46; 7.36≤f12 / f≤8.88; 23.55 < f78 / f < 36.89; -47.86 < f91 / f < -22.19.

[0023] In this invention, considering the aberrations of the optical system and the different focal distances, the focal lengths, refractive indices, and radii of curvature of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the ninth lens 9, the tenth lens 10, the eleventh lens 11, and the twelfth lens 12 respectively satisfy the following conditions:

[0024] Focal length: "+" indicates that the lens has positive power, and "-" indicates that the lens has negative power. The unit is mm. Radius of curvature: "+" indicates that the surface bends toward the image plane, and "-" indicates that the surface bends toward the object plane. The unit is mm.

[0025] In this invention, f is the total focal length of the lens, TTL is the total optical length of the lens, OBFL is the optical back focal length of the lens, the optical back focal length of the lens is the distance from the point on the image side of the twelfth lens closest to the image plane to the image plane, and IC is the full image height of the chip paired with the lens system. They satisfy the following relationship: IC / TTL ≥ 0.14; TTL / f≤20.6; OBFL / TTL ≥ 0.1; In this invention, the aperture of the lens is F#, which satisfies F#≥1.0; The field of view of the lens is FOV, which satisfies FOV≤200°; The total optical length of the lens is TTL, which satisfies TTL≤30mm; The total focal length of the lens is f, which satisfies f≥1.38mm; The optical back focal length of the lens is OBFL, which satisfies OBFL≥3mm.

[0026] The following provides specific embodiments based on the above-described configuration of this utility model, thereby specifically illustrating the large-aperture day-night confocal fisheye lens of this utility model. To better understand and implement this utility model, it will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0027] The data summary of the specific embodiments of this utility model is shown in Table 1 below.

[0028] Table 1

[0029] Example 1 refer to Figure 1The diagram shown is a schematic representation of the optical structure of Embodiment 1. In this embodiment, the lens has a field of view (FOV) of 186°, an aperture value (F#) of 1.0, a total focal length (f) of 1.38 mm, a total optical length (TTL) of 30 mm, and an optical back focal length (OBFL) of 3.7 mm.

[0030] In this embodiment, the lenses are arranged sequentially from the object side to the image side along the lens optical axis: The first lens 1 is a spherical glass lens with negative optical power, the object side of which is convex and the image side is concave. The second lens 2 is a spherical glass lens with negative optical power, whose object side is convex and image side is concave. The third lens 3 is a spherical glass lens with negative optical power, whose object side is convex and image side is concave. The fourth lens 4 is a spherical glass lens with negative optical power, and its object side and image side are concave. The fifth lens 5 is a spherical glass lens with positive optical power, and its object side and image side are both convex. The sixth lens 6 is a spherical glass lens with positive optical power, and its object side and image side are both convex. Aperture stop 13 is located between the sixth lens 6 and the seventh lens 7; The seventh lens 7 is a spherical glass lens with negative optical power, whose object side is convex and image side is concave. The eighth lens 8 is a spherical glass lens with positive optical power, and its object side and image side are both convex. The ninth lens 9 is a spherical glass lens with positive optical power, and its object side and image side are both convex. The tenth lens 10 is a spherical glass lens with negative optical power, whose object side is concave and image side is convex. The eleventh lens 11 is a spherical glass lens with positive optical power, and its object side and image side are both convex. The twelfth lens 12 is a spherical glass lens with positive optical power, its object side is convex and its image side is concave. Filter 14 is disposed on the image side of the twelfth lens; The protective glass 15 and the image acquisition element 16 are integrated on the image acquisition element 16, which is located on the image side of the protective glass 15.

[0031] In this system, the image-side surface of the seventh lens 7 and the object-side surface of the eighth lens 8 are cemented together to form a first cemented lens; the image-side surface of the ninth lens 9 and the object-side surface of the tenth lens 10 are cemented together to form a second cemented lens. These two sets of cemented lenses effectively control chromatic aberration and reduce tolerance sensitivity issues such as tilting and eccentricity that occur during lens assembly.

[0032] In this embodiment, the radius of curvature (in mm), center thickness d (in mm), refractive index (ND), and Abbe constant (VD) of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the ninth lens 9, the tenth lens 10, the eleventh lens 11, and the twelfth lens 12 are shown in Table 2.

[0033] Table 2

[0034] In Table 2, the surface numbers are assigned according to the order of the surfaces of each lens. "S11" represents the object side of the first lens, "S12" represents the image side of the first lens, and so on. The radius of curvature represents the curvature of the lens surface. A positive value means that the surface bends towards the image plane, and a negative value means that the surface bends towards the object plane. "Infinity" means that the surface is flat. The thickness represents the central axial distance from the current surface to the next surface. The refractive index represents the ability of the current lens material to deflect light. The Abbe number represents the dispersion characteristics of the current lens material.

[0035] refer to Figure 2 The figure shows the MTF curves of the lens in this embodiment at different fields of view with a visible light wavelength of 0.435-0.656μm and a spatial frequency of 200lp / mm. The horizontal axis represents the spatial frequency, and the vertical axis represents the MTF value. As can be seen from the figure, at a spatial frequency of 200lp / mm, the MTF value is generally above 0.3 except for the maximum field of view, and the MTF value at the maximum field of view is also above 0.2. This indicates that the lens has high resolution and can be matched with chips with higher pixel counts.

[0036] refer to Figure 3 The figure shows the MTF curve of the lens in this embodiment at an infrared wavelength of 0.85μm and a spatial frequency of 200lp / mm. As can be seen from the figure, at a spatial frequency of 200lp / mm, the MTF value of the lens across the entire field of view is 0.25 or higher, and the MTF value at the center field of view is 0.6 or higher. This ensures that the lens can capture clear images at night, enabling all-weather high-definition monitoring.

[0037] refer to Figure 4 , Figure 5The figures show the MTF defocus curves of the lens in this embodiment at high temperature (+85℃) and low temperature (-40℃) with a visible light wavelength of 0.435-0.656μm and a spatial frequency of 125lp / mm. As can be seen from the figures, the defocus amount is less than 2μm at both high temperature (+85℃) and low temperature (-40℃), which ensures that the lens has high resolution at both temperatures, enabling high-definition image capture.

[0038] refer to Figure 6 The figure shows the relative illuminance curve of the lens at 0.546μm visible light in this embodiment. As can be seen from the figure, the relative illuminance at the maximum field of view is above 40%, which means that the light intake is sufficient and the lens can be used even in relatively dark environments. There is no vignetting at the edge of the field of view in the actual shooting image.

[0039] Example 2 refer to Figure 7 The diagram shown is a schematic representation of the optical structure of Embodiment 2. In this embodiment, the lens field of view (FOV) is 180°, the lens aperture (F#) is 1.0, the total focal length of the lens optical system (f) is 1.45mm, the total optical length (TTL) is 30mm, and the optical back focal length (OBFL) is 3mm.

[0040] In this embodiment, the lens is arranged along the optical axis from the object side to the image side in the same way as in embodiment 1. The difference is that the aperture stop is arranged between the fifth lens and the sixth lens.

[0041] In this embodiment, the radius of curvature (unit: mm), center thickness d (unit: mm), refractive index (ND), and Abbe constant (VD) of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the ninth lens 9, the tenth lens 10, the eleventh lens 11, and the twelfth lens 12 are shown in Table 3.

[0042] Table 3

[0043] In Table 3, the surface numbers are assigned according to the order of the surfaces of each lens. "S11" represents the object side of the first lens, "S12" represents the image side of the first lens, and so on. The radius of curvature represents the curvature of the lens surface. A positive value means that the surface bends towards the image plane, and a negative value means that the surface bends towards the object plane. "Infinity" means that the surface is flat. The thickness represents the central axial distance from the current surface to the next surface. The refractive index represents the ability of the current lens material to deflect light. The Abbe number represents the dispersion characteristics of the current lens material.

[0044] refer to Figure 8The figure shows the MTF curves of the lens in this embodiment at different fields of view with a visible light wavelength of 0.435-0.656μm and a spatial frequency of 200lp / mm. The horizontal axis represents the spatial frequency, and the vertical axis represents the MTF value. As can be seen from the figure, at a spatial frequency of 200lp / mm, the MTF value of the lens across the entire field of view, except for the maximum field of view, is above 0.3, and the MTF value at the maximum field of view is also above 0.2. This indicates that the lens has high resolution and can be matched with chips with higher pixel counts.

[0045] refer to Figure 9 The figure shows the MTF curve of the lens in this embodiment at an infrared wavelength of 0.85μm and a spatial frequency of 200lp / mm. As can be seen from the figure, at a spatial frequency of 200lp / mm, the MTF value of the lens across the entire field of view, except for the maximum field of view, is above 0.3. This ensures that the lens can capture clear images at night and achieve all-weather high-definition monitoring.

[0046] refer to Figure 10 , Figure 11 The figures show the MTF defocus curves of the lens in this embodiment at high temperature (+85℃) and low temperature (-40℃) with a visible light wavelength of 0.435-0.656μm and a spatial frequency of 125lp / mm. As can be seen from the figures, the defocus amount is less than or equal to 4μm at both high temperature (+85℃) and low temperature (-40℃), which ensures the lens's resolution at these temperatures, enabling high-definition image capture.

[0047] refer to Figure 12 The figure shows the relative illuminance curve at 0.546μm for visible light in this embodiment. As can be seen from the figure, the relative illuminance at the maximum field of view is above 40%, which is sufficient to ensure that the lens can be used even in relatively dark environments, and there is no vignetting at the edge of the field of view in the actual shooting image.

[0048] As can be seen from the MTF curves, defocus curves, and relative illumination curves of the various embodiments above, the optical lens provided by this utility model has advantages such as large aperture, high resolution, compatibility with high-pixel chips, relatively high relative illumination, and the ability to achieve day and night co-focusing under high and low temperature environments.

[0049] The above description merely illustrates several embodiments of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and this utility model also intends to include these modifications and variations.

Claims

1. A large-aperture day and night confocal fisheye lens, characterized in that: Set sequentially from the object side to the image side along the lens optical axis: The first lens is a spherical glass lens with negative optical power; The second lens is a spherical glass lens with negative optical power; The third lens is a spherical glass lens with negative optical power; The fourth lens is a spherical glass lens with negative optical power; The fifth lens is a spherical glass lens with positive optical power; The sixth lens is a spherical glass lens with positive optical power; The seventh lens is a spherical glass lens with negative optical power; The eighth lens is a spherical glass lens with positive optical power; The ninth lens is a spherical glass lens with positive optical power; The tenth lens is a spherical glass lens with negative optical power; The eleventh lens is a spherical glass lens with positive optical power. The twelfth lens is a spherical glass lens with positive optical power.

2. The large-aperture day and night confocal fisheye lens according to claim 1, characterized in that: The aperture of the lens is F#, which satisfies F#≥1.

0.

3. The large-aperture day and night confocal fisheye lens according to claim 1, characterized in that: The lens satisfies the following relationship: IC / TTL ≥ 0.14; OBFL / TTL ≥ 0.1; In the formula, TTL is the total optical length of the lens, OBFL is the optical back focal length of the lens, and IC is the full-image height of the chip paired with the lens system.

4. The large-aperture day and night confocal fisheye lens according to claim 1, characterized in that: The lens satisfies the following relationship: TTL / f≤20.6; In the formula, f is the total focal length of the lens, and TTL is the total optical length of the lens.

5. The large-aperture day and night confocal fisheye lens according to claim 1, characterized in that: The total focal length of the lens is f, which satisfies f≥1.38mm; the total optical length of the lens is TTL, which satisfies TTL≤30mm.

6. The large-aperture day and night confocal fisheye lens according to claim 1, characterized in that: The lens also satisfies the following relationship: -11.1≤f1 / f≤-10.81; -8.36≤f² / f≤-7.35; -8.75≤f3 / f≤-6.79; -2.40≤f4 / f≤-2.24; 3.64≤f5 / f≤4.00; 7.56≤f6 / f≤8.97; -4.61≤f7 / f≤-3.76; 3.82≤f8 / f≤4.16; 4.01≤f9 / f≤4.36; -3.68≤f10 / f≤-3.06; 5.69≤f11 / f≤6.46; 7.36≤f12 / f≤8.88; In the formula, f is the total focal length of the lens, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, f8 is the focal length of the eighth lens, f9 is the focal length of the ninth lens, f10 is the focal length of the tenth lens, f11 is the focal length of the eleventh lens, and f12 is the focal length of the twelfth lens.

7. The large-aperture day and night confocal fisheye lens according to claim 1, characterized in that: The image-side surface of the seventh lens and the object-side surface of the eighth lens are cemented together to form a first cemented lens. The focal length of the first cemented lens is f78, which satisfies: 23.55 < f78 / f < 36.89, where f is the total focal length of the lens.

8. The large-aperture day and night confocal fisheye lens according to claim 1, characterized in that: The image-side surface of the ninth lens and the object-side surface of the tenth lens are cemented together to form a second cemented lens. The focal length of the second cemented lens is f91, which satisfies the condition: -47.86 < f91 / f < -22.19, where f is the total focal length of the lens.

9. A large-aperture day and night confocal fisheye lens according to claim 1, characterized in that: The object-side surface of the first lens is convex, and the image-side surface is concave. The object-side surface of the second lens is convex, and the image-side surface is concave. The object-side surface of the third lens is convex, and the image-side surface is concave. The object side of the fourth lens is concave, and the image side is also concave. The object-side surface of the fifth lens is convex, and the image-side surface is also convex. The object-side surface of the sixth lens is convex, and the image-side surface is also convex. The object-side surface of the seventh lens is convex, and the image-side surface is concave. The object-side surface of the eighth lens is convex, and the image-side surface is also convex. The object-side surface of the ninth lens is convex, and the image-side surface is also convex. The object-side surface of the tenth lens is concave, and the image-side surface is convex. The object-side surface of the eleventh lens is convex, and the image-side surface is also convex. The object side of the twelfth lens is convex, while the image side can be concave.

10. A large-aperture day and night confocal fisheye lens according to claim 1, characterized in that: Also set along the lens optical axis: An aperture stop is provided, wherein the aperture stop is disposed between the sixth lens and the seventh lens, or the aperture stop is disposed between the fifth lens and the sixth lens; A filter, wherein the filter is disposed on the image-side surface of the twelfth lens; A protective glass and an image acquisition element, wherein the protective glass is integrated on the image acquisition element, and the image acquisition element is disposed on the image side of the protective glass.

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